Abstract: 【Objective/Meaning】The relationship between economic development and urbanization has always been a hot topic in economic research. Exploring the relationship between the two is conducive to promoting the sustainable development of cities and society in China. 【Methods/Procedures】Based on the data of the west-straits economic zone from 2011 to 2017, MaxDEA 8.0 software was used to build the SBM-DEA window model with bounded output to calculate the urbanization efficiency, and the entropy method was used to calculate the economic development level. On this basis, the dynamic relationship of coupling coordination between the two was further analyzed. 【Results/Conclusions】The urbanization efficiency, economic development level of the west-straits economic zone and their coupling degree all had positive trend. During the research period, the average urbanization efficiency increased from 0.851 to 0.860, the average economic development level increased from 0.218 to 0.388, and the coupling degree increased from 0.772 to 0.906. It could be seen that the economic development level presented an inverted U shape distribution relation to the coupling degree, and there was also an inverted U shape distribution relation between the economic development level and urbanization efficiency.